An Afghan National Army (ANA) soldier assigned to the Mobile Strike Force Kandak fires a RPG-7 rocket-propelled grenade launcher during a live-fire exercise supervised by the Marines with the Mobile Strike Force Advisor Team on Camp Shorabak, Helmand province, Afghanistan, May 20, 2013. The Marines with the Mobile Strike Force Advisor Team instructed and mentored their ANA counterparts on how to properly utilize their weapons systems. (Photo by SSgt Ezekiel R. Kitandwe/RCT 7)

Russian cosmonaut Alexander Skvortsov, Expedition 40 flight engineer, attired in a Russian Orlan spacesuit, participates in a session of extravehicular activity (EVA) in support of science and maintenance on the International Space Station on August 18, 2014. During the five-hour, 11-minute spacewalk, Skvortsov and cosmonaut Oleg Artemyev (out of frame) deployed a small science satellite, retrieved and installed experiment packages and inspected components on the exterior of the orbital laboratory. (Photo by NASA)

Darlene Eddy packages up a chocolate Easter bunny that she made in her store Amazing Chocolates on March 28, 2013 in Hollywood, Florida. As Easter Sunday approaches chocolatiers are busy manufacturing many different types of delights for the holiday when Americans spend roughly $1.9 billion on Easter candy, second only to Halloween in candy consumption. Around ninety million chocolate Easter bunnies are produced each year, from white to dark chocolate, and with an unlimited varieties of styles. (Photo by Joe Raedle)

Passengers check their mobile devices as a bin is full of garbage during a protest by the cleaning staff at Barcelona's airport, Spain, December 1, 2016. (Photo by Albert Gea/Reuters)

A boy uses a mobile phone as he sits inside his father's snacks shop along a road in Kolkata, India, February 22, 2016. (Photo by Rupak De Chowdhuri/Reuters)

Children pat an elephant at the mobile Diva circus in the town of Molodechno, some 70 kilometers northwest of Minsk on September 3, 2015. (Photo by Sergei Gapon/AFP Photo)

A staff member sets up a ROBOTLEO robot at the Global Mobile Internet Conference (GMIC) 2017 in Beijing, China April 28, 2017. (Photo by Jason Lee/Reuters)

Singers Chris Daughtry and Rachel Platten attend the 2017 Billboard Music Awards at T-Mobile Arena on May 21, 2017 in Las Vegas, Nevada. (Photo by Chris Polk/BBMA2017/Getty Images for DCP)